CROSS-REFERENCE TO RELATED APPLICATIONS
The present application claims priority under 35 U.S.C. xc2xa7119 of German Patent Application No. 197 07 090.6, filed on Feb. 24, 1997, the disclosure of which is express incorporated by reference herein in its entirety.
1. Scope of the Invention
The present invention relates to a vehicle wheel with a pneumatic tire mounted on a wheel rim. The vehicle tire includes a tire tread, two side-walls, a carcass, reinforcing elements, and two tire beads with bead cores. The vehicle tire also includes an emergency support body mounted on the wheel rim. The emergency support body is arranged inside the pneumatic tire to provide an emergency rolling surface to support the tire in the event of failure.
2. Discussion of Background Information
A vehicle wheel similar in general to one discussed above is provided with an emergency support body as disclosed, e.g., in German Patent Application No. DE 35 07 046. In this wheel, an emergency roll frame is comprised of an exterior, metallic reinforcement ring and a cushion ring arranged between the reinforcement ring and the wheel rim. While the cushion ring provides relatively good radial flexing, the combination of an insufficient axial fixture with the substantially planar cross-section metallic reinforcement ring demonstrates a disadvantage that, during an emergency, the lateral guide forces or cohesive forces, which prevent an unseating or peeling off of the tire from the wheel rim, cannot be exerted in a satisfactory manner.
Taking the lateral guide forces into account, an optimized solution is shown, e.g., in German Patent No. DE 956 380, which shows a vehicle wheel with an emergency support body formed as a completely rigid metal piece connected to the wheel rim. The vehicle wheel also shows a peripheral notch in the emergency rolling surface to engage a toothed, inward-facing projecting part of the running surface sub-structure. In the event of an emergency, a form-fitting shape is created in the axial direction, between the emergency roll frame and the tire, so that the tire bead is prevented from stripping off the wheel rim. A disadvantage of a vehicle wheel provided with such an emergency roll frame is the additional weight that arises from the toothed and inward-facing rubber bead to be inserted in the slot and the weight of the emergency rolling surface bolted together with a two-piece wheel rim in an elaborate manner. Further, only a metal elastic flexing is possible for the emergency roll, so that a very xe2x80x9chardxe2x80x9d and uncomfortable rolling occurs in the event of a breakdown.
In the two above-mentioned arrangements, and with other emergency support bodies known in the prior art, another disadvantage is that, due to an unfavorable load distribution during the introduction of forces acting on the periphery of the emergency support body, load peaks can occur on the wheel rim sufficient to deform the wheel rim.
The present invention provides a vehicle wheel for pneumatic tires with an emergency support body. During an emergency roll, the emergency support body may maintain the drive pattern that continues to be safe and maintain a sufficiently resilient rolling motion and may safely transfer lateral guide forces without an excessive increase in weight. The emergency support body may also provide a load distribution to substantially prevent acting forces from damaging the wheel rim.
The emergency rolling surface is formed by a radially exterior surface of a ring torus with a bowl-shaped cross section. The ring torus axially extends from an axial center of the wheel rim to both sides of the rim, i.e., over a partial area of the wheel rim width. The ring torus has a cross-sectional contour in its axially exterior sections that forms a first curvature open to the wheel rim, i.e., radially inward, and a cross-sectional contour in a section between the axially exterior sections that forms a second curvature open to the a highest point of the tire, i.e., radially outward. The first and second curvatures may include one or several inter-connecting radii of curvature and the ring torus with a bowl-shaped cross-section may be supported on the wheel rim by one or several supporting elements. The reinforcement can occur directly on the wheel rim, at gliding units adapted to the wheel, or via guide rollers and roller bearings, so that friction during an emergency run is minimized.
Through the contour, which essentially involves dividing the emergency rolling surface into two shoulder regions and a more or less highly pronounced recoil region, a rolling behavior of the tire, i.e., in the event of a break down, results in accordance with the curvature shape, the curvature and the force absorption and elasticity characteristics of the support elements. While these characteristics are different from the normal case, the tire, under emergency conditions, maintains the ability to drive the vehicle, while only slightly differing from handling during normal running conditions.
The ability to absorb lateral guide forces is especially pronounced in the present invention. This is due to the recoil provided in the middle regions of the emergency rolling surface that enable the middle sections of the tire tread or the sub-structure to conform to the curvature. Thus, with respect to lateral forces, the tire of the present invention creates a form-fitting shape that reduces the tensile forces affecting the side-walls to a level that is safe for the driving conditions. In this manner, peeling of the tire bead from the wheel rim is substantially prevented. Further, the radii of curvature of neighboring portions of the emergency surface are designed to gradually merge with each other and to work with the tread thickness of the tire to substantially prevent point loads or linear loads that could destroy the tire tread.
A further advantage of a ring torus with a bowl-shaped cross-section provided with curvatures, as discussed above, is that during an emergency roll, very high point loads, e.g., running over a sidewalk or curb, may be absorbed. Further, through the increased rigidity and shape of the ring torus with a bowl-shaped cross-section, an even load distribution is provided that is not detrimental to the wheel rim.
Generally, the ring torus with a bowl-shaped cross section is formed to axially and symmetrically extend from an equatorial plane of the tire, i.e., an axial center, over a portion of the width of the wheel rim. However, when utilized in vehicles with a steep king pin angle, i.e., with a steeply inclined positioning of the wheels, symmetrical contouring may not be necessary and the areas of curvature to the inclination angle of the tires may be accordingly adjusted.
Considering the compromise between weight optimization and rolling behavior, an advantageous embodiment of the present invention is that the axially exterior sections, i.e., with the first curvatures, rise at most to one-half, and preferably up to one-third, of the tire cross-sectional height of the tire. In a tire size of, e.g., 195/65 with a wheel rim diameter of 15 inches, the first curvatures may be spaced 42 mm from the wheel rim shoulder. Thus, a sufficient height of two-thirds of the tire cross-sectional height is available for normal driving operations and the flexing that occurs there.
In conjunction with another embodiment of the present invention, the ring torus, in the region of the second curvature, has a minimum diameter greater than a diameter of wheel clinch devices. Further, the emergency support bodies of the present invention are easily adjustable to conventional tire sizes and wheel rim dimensions. In this manner, during an emergency roll, excessive flexing in the lateral sections of the tire may be substantially prevented.
In an advantageous embodiment of the present invention, the supporting elements may be formed to extend from the axially exterior sections and as substantially planar annular disks supported on the wheel rim.
Depending on manufacture of the emergency frame is as a single piece or as multiple parts, one advantage, i.e., from a manufacturing standpoint, lies in that a press or a roll-molding process may be utilized proceeding from a ring-like edge, or a forming or injection process can be utilized with simple tools. Another advantage of the present invention is that, with respect to the assembly, the emergency roll frame can be conformed or adapted to a shape and width of the wheel rim in a particularly easy manner. Further, the suspension behavior or characteristics of the emergency roll frame may be influenced as a function of the support body.
Several adjoining annular disks can, e.g., be utilized as supporting elements and angled toward the axial center of the vehicle wheel. Each disk may be positioned at an angle directed inward toward the axle or outward away from the axle, e.g., shaped like a spring washer set. In this manner, another possibility exists for the adjustability with respect to the elastic force absorption capability of the emergency support body.
In an advantageous embodiment of the present invention, an annular disk may be coupled to the ring torus, as an extension of the axially exterior section. The annular disk may be positioned at an angle of, e.g., between approximately 75xc2x0 and 90xc2x0, and preferably at approximately 83xc2x0 to the wheel axis. In this manner, a cross-sectional view of shows a smooth transition from the contour of the ring body to the planar annular disk without any ridges being created or formed.
The joint effect of the curvature of the emergency rolling surface and the flexible brace (planar annular disk) positioned at an angle of approximately 83xc2x0 to the axle axis is sufficient for a good emergency rolling behavior. Further, because of the relatively steep degree of inclination of the planar annular disk, a minimum of material is required to form the emergency support body. This, reduces the weight of the tire.
With respect to usage on special vehicles, e.g., on two-wheel vehicles, it can be advantageous to form the supporting elements as one or more support rings positioned between the ring torus and the wheel rim. Thus, it is possible to design emergency support bodies for narrow wheel rims. Further, stability can be advantageously improved when the support elements are formed substantially across the width of the ring torus.
In an embodiment having a plurality of supporting elements positioned between the ring torus and the wheel rim, the wheel rim may be advantageously formed to have reduced elasticity in the transition areas to create of an articulation point. With the possibility of an elastic bending of the supporting elements, the present invention enables a simple assembly of the emergency support body on integral standard wheel rims.
The supporting elements may be formed to secure seating of the tire beads, even in an event of failure. The supporting elements may be supported on the wheel rim in the areas neighboring the tire beads to serve as tire bead securing devices. In this manner, the humps and the projecting parts are simplified, thereby reducing the manufacturer"" costs.
An advantageous embodiment of the present invention is that the supporting element and the ring torus may be made of the same material, preferably aluminum or alloyed aluminum. This enables manufacturing to be easier and simpler, and also enables later sorting and separation of remaining materials, e.g., for recycling, to be performed with low expenditure.
An embodiment made of aluminum may require a two-piece wheel rim or a pre-shaped wheel rim, which, after mounting the tire and emergency support body, is processed to its final shape and size.
In a further embodiment, in which the supporting elements and the ring torus demonstrate varying elasticities, the supporting elements may be made of, e.g., rubber elastic or elastoplastic material and the ring torus may be made of, e.g., aluminum or aluminum alloy. In this case, because of the well-moldable rubber elastic materials of the supporting elements, normal standard wheel rims can be used. This enables a simple refitting of vehicle wheels already in operation is made possible.
The supporting elements may be made of, e.g., viscoelastic, elastoplastic or viscoplastic materials. These materials may be adjusted in their characteristics by using various polymer and rubber mixtures with different fillers and additives.
Polyurethane foams or other elastomeric foams, for example, can be used as elastic rubber materials.
The alloy AlMnSi 08 has been shown to be an effective aluminum material, such that the ring torus is formed, for the most part, with a thickness of, e.g., between approximately 4 and 6 mm, and the rubber elastic or elastoplastic materials of the supporting elements are formed with a thickness of, e.g., approximately 8 mm.
In another advantageous design, the support elements may be made of elastic rubber material and the ring torus may be composed of a synthetic material that is comparatively harder than elastic rubber or elastoplastic material, i.e., composed of a synthetic material with a higher modulus of elasticity and greater firmness. In the injection molding process, this may prove advantageous in simplifying manufacturing procedure because only one more material mixture must be fed into the available mold via one or several supplementary nozzles during the injection in accordance with the bi-injection or co-injection process. In this manner, the gradient for the consistencies and the elasticities may be controlled.
This advantageous design can be further refined, in that the ring torus may be composed of fiber-reinforced synthetic material. In such cases, available injection molds or synthetic material female molds may be partially lined, e.g., with fiberglass mats. After this arrangement, only one short injection process is necessary for production.
Naturally, the use of synthetic materials in place of aluminum reduces the overall weight. This weight reduction has a further advantage that the optimal combination of material can be provided for each respective type of transport vehicle and for stress by weight on the wheels.
The bonding of the various materials with each other may be provided via gluing, vulcanization, cross-linking, or via interlocking of forms hooked into each other. In this regard, the appropriate bonding method can be chosen for each design from the many methods available. In the event that particularly stable all-metal designs of the emergency support bodies are necessary, e.g., as with wheels for heavy-duty government vehicles, an advantageous design exists if the support elements are composed of spring steel and the ring torus is composed of aluminum. This results in a high loading capacity of the emergency support body with a simultaneous, relatively modest increase in the weight of the wheel.
Besides the use and design of elastic material characteristics of the support elements, another advantageous design of the present invention exists when the support elements demonstrate humps, slots, or notches that have a suspension effect in the radial direction. In this event, components of the support elements which are elastic in shape may be used for providing an optimized, comfortable rolling behavior.
The present invention may provide an emergency support body formed as a surrounding ring torus with a bowl-shaped cross-section that includes at least two sections that are arched radially outwards and are separated from each other by a radial contraction (depression). The at least two axially exterior peripheral areas provide the necessary support.
Such an emergency support body, which is generally only made out of one material, may already include support elements in its lateral areas and may be easily adapted in any relation whatsoever to the lateral forces and stress on its emergency rolling surface during an emergency run. The single-piece design also allows a simple molding process and, thus, cost-effective manufacturing.
In another advantageous design, the ring torus may be reinforced with support ribs located on its under side and directed toward the wheel rim. The support ribs may run in a circumferential or axial direction. Such a design allows peak loads to be absorbed and a further saving of weight by reducing the wall thickness in less strained areas.
Likewise, a pure alteration or adaption of the wall thickness of the emergency support body can also help to enable weight minimization, e.g., either in the areas of the support elements or over the axial extension of the ring torus with a bowl-shaped cross section.
Further, an emergency support body in accordance with the present invention may be utilized fastened to a wheel rim inside a pneumatic vehicle tire.
Accordingly, the present invention is directed to a vehicle wheel that includes a pneumatic tire mounted on a wheel rim. The pneumatic tire includes a tire tread, two side-walls, a carcass, reinforcing elements, and two tire beads with bead cores. The vehicle wheel also includes an emergency support body, mounted on the wheel rim and positioned inside the pneumatic tire. The emergency support body includes an emergency rolling surface to support the tire in case of a failure of the pneumatic tire. The emergency rolling surface includes a radially exterior surface of a ring torus with a bowl-shaped cross section, and the ring torus includes axially exterior sections having cross-sectional contours with first curvatures open to the wheel rim and an intermediate section positioned between the axially exterior sections having a contour with a second curvature open to a crest point of the pneumatic tire. The first and second curvatures include at least one radius of curvature and at least one supporting element is positioned to support the ring torus on the wheel rim.
In accordance with another feature of the present invention, the axially exterior sections may radially extend from the rim a distance less than approximately one-half of a cross-sectional tire height. Further, the axially exterior sections may radially extend from the rim a distance less than approximately one-third of a cross-sectional tire height.
In accordance with another feature of the present invention, the second curvature of the intermediate section may have a minimum diameter greater than an exterior diameter of wheel rim clinch devices.
In accordance with still another feature of the present invention, the at least one supporting element may include a substantially planar disk ring mounted to the wheel rim and may form extensions of the axially exterior areas. Further, the at least one supporting element may include a plurality of disk rings coupled to each other, and each disk ring may be positioned at an angle to a wheel axis. Alternatively, the substantially planar disk ring may include an annular disk coupled to extend from the axially exterior section of the ring torus without the creation of a ridge and the annular disk may be positioned at an angle between approximately 75xc2x0 and 90xc2x0 to a wheel axis. In another alternative, the at least one support element may be supported on the wheel rim in an area adjacent the tire beads to secure the tire bead to the rim.
In accordance with a further feature of the present invention, the at least one support element may be composed of at least one support ring positioned between the ring torus and the wheel rim. Further, the at least one support ring may be further positioned substantially along a width of the ring torus. Alternatively, the at least one support rings may have areas of reduced elasticity for coupling with the ring torus to create an articulation point.
In accordance with another feature of the present invention, the at least one support element may be composed of one of rubber elastic and elastoplastic material and the ring torus may be composed of one of aluminum and an aluminum alloy.
In accordance with still another feature of the present invention, the at least one support element may be composed of one of rubber elastic and elastoplastic material and the ring torus may be composed of a synthetic material harder than the material composing the at least one support element. Further, the ring torus may be composed of a fiber-reinforced synthetic material. Still further, the at least one support element may be composed of one of rubber elastic and elastoplastic material and having a wall thickness greater than a wall thickness of the ring torus.
In accordance with a further feature of the present invention, the ring torus may be composed of aluminum and the at least one support element may be composed of spring steel.
In accordance with a still further feature of the present invention, the at least one support element includes at least one of humps, slots, and notches that produce a radially directed suspension effect.
The present invention is directed to a vehicle wheel that includes a pneumatic tire mounted on a wheel rim. The pneumatic wheel includes a tire tread, side walls, a carcass, reinforcing elements, tire beads with bead cores. The vehicle wheel also includes an emergency support body, mounted on the wheel rim and positioned inside the pneumatic tire, that includes an emergency rolling surface to support the pneumatic tire in case of failure. The emergency support body includes a surrounding ring torus with a bowl-shaped cross section having at least two radially outwardly arched sections forming axially exterior peripheral areas separated from each other by a radial depression and the emergency support body is supported over both axially exterior peripheral areas.
In accordance with another feature of the present invention, the vehicle wheel further includes ribs for reinforcing the ring torus being located on an under side of the ring torus. The ribs may be positioned to point toward the wheel rim and extending in one of a circumferential and axial direction.
In accordance with another feature of the present invention, the emergency support body may be composed of one of aluminum and aluminum alloy.
The present invention is directed to an emergency support body for use in a pneumatic vehicle tire. The emergency support body includes a ring torus with a bowl-shaped cross section. The ring torus has axial end sections including radially outwardly arched sections and an intermediate section coupling the axial end sections. The emergency support body also includes support elements coupled to extend from the axial end sections and adapted to be coupled to a rim of a vehicle tire.
In accordance with another feature of the present invention, the support elements may extend from the axial end sections such that, when mounted to the rim, the support elements form an angle of between approximately 75xc2x0 and 90xc2x0 to a rim axis.
In accordance with another feature of the present invention, the support elements may be arranged to divergently extend from the axial end sections.
In accordance with still another feature of the present invention, the support elements may include a spring washer set.
In accordance with a further feature of the present invention, the support elements may include two adjoining annular disks. Further, the two adjoining annular disks may be directed inwardly.
In accordance with a still further feature of the present invention, the support elements may include an annular disk. Further, the annular disk may include a hump, which may be directed inwardly.
In accordance with yet another feature of the present invention, the emergency support element may include ribs extending from the ring torus in one of a radial and axial direction.